A semiconductor wafer is formed with a circuit and then bonded to an adhesive sheet, followed by being arranged to each step of cutting (dicing) into small element pieces, washing, drying, drawing (expanding) of the adhesive sheet, peeling (picking up) the small element pieces from the adhesive sheet, mounting, and the like. The adhesive sheet (dicing tape) used in these steps is desired to have sufficient tack strength for the cut small element pieces (chips) from the dicing step to the drying step while having reduced tack strength to cause no adhesive transfer in the picking up step.
Such an adhesive sheet includes a sheet made by applying an adhesive layer that develops polymerization curing reaction by ultraviolet rays and the like on a substrate transmissive to activating rays, such as ultraviolet rays and/or electron beams. Using such an adhesive sheet, a method of irradiating the adhesive layer with ultraviolet rays and the like after the dicing step for polymerization curing of the adhesive layer to reduce the tack strength, followed by picking up the cut chip is employed.
As examples of such an adhesive sheet, PTLs 1 and 2 disclose adhesive sheets with a substrate surface on which an adhesive is applied containing a compound (polyfunctional oligomer), for example, capable of being three dimensionally networked by activating rays and having a photopolymerizable unsaturated double bond in a molecule.